The operation of gas turbines is attended by exhaust gas streams of large volumes and suddenly attained high temperatures which streams are well adapted for use in cogeneration.
A gas turbine exhaust system has, accordingly, a section including a heat recovering steam boiler and a bypass section. During cogeneration, the bypass section must be closed by the use of one or more dampers and when the steam boiler is to be placed out of service for any reason, the section leading thereto must also be closed by the use of one or more dampers. Dampers for use in such exhaust systems may be of either a louver type or a guillotine type but are herein discussed as of the latter type.
Because of the sudden build-up of high temperatures during the operation of gas turbines, it is essential that each such damper be so constructed that it will accommodate thermal expansion forces that would otherwise destroy the effectiveness of the means sealing the clearances between the damper blade and the framework by which it is supported.